1. Field of the Invention
The present invention relates to a map display apparatus that determines a route from a present position to a destination and displays the determined route in the form of a line on a map.
2. Description of Related Art
A typical map display apparatus for a car navigation system displays a route line on a map in order to indicate a route (navigation route) to a destination and guide a user to the destination. It is preferable that a user can quickly recognize a navigation route from the displayed route line even if the user is driving the vehicle.
In general, the route line is displayed as a wide line on a map with the color of the route line being different from that of a road line. Further, an arrow mark is displayed over the route line so that a user can easily recognize a direction to the destination (see JP-H5-19691A for example).
In this relation, the inventor of the present application has found out the followings.
In some case, when a route line is superimposed on a map, it becomes difficult to recognize information shown on the map due to the route line. For example, when roads on a map are displayed in different colors according to road type and when the color of a certain road is covered by the route line, the type of the certain road becomes unperceivable. In addition, in some cases, the route line may partially cover a symbol, a text, or an intersection shape etc. on the map.
If the route line is displayed as, for example, a thin line or a broken line to reduce an area covered by the route line, it becomes easier to recognize information on a map; however, visibility of a route line is reduced because it becomes difficult to find out a route line upon viewing a display screen or the navigation route is displayed in an indefinite manner.